Surface properties and biological behaviour of Si-DLC coatings fabricated by a multi-target DC–RF magnetron sputtering method for medical applications

•DLC and Si-DLC coatings were prepared by a multi-target DC–RF magnetron sputtering method.•The content of Si in DLC films varied from ~ 4 at.% up to ~ 16 at.%.•Increasing concentration of Si suppresses the platelet adhesion on the surface and decreases their activation level.•Si-DLC coatings are not cytotoxic regardless of the silicon concentration.

The Si-incorporated diamond-like carbon (DLC) coatings deposited on AISI 316 LVM medical steel using magnetron sputtering method are currently not widely described in the literature, especially in terms of their biological response. Therefore, in this study both the haemocompatibility and cytotoxicity, as well as the surface properties of the Si-DLC films prepared by multi-target DC–RF magnetron sputtering were assessed. According to the XPS analysis the content of Si in the obtained coatings varied from ~ 4 at.% up to ~ 16 at.%. SEM investigations showed that the surface of the Si-DLC coatings is uniform and homogenous without any local defects. The surface energy measurements and FTIR analysis demonstrated that hydrophilicity and polarity of the examined surfaces changes with the varying Si-concentration. The evaluation of biological response towards the deposited coatings revealed that the increasing concentration of Si suppresses the platelet adhesion and decreases their activation level. Moreover, the results of the live/dead test indicated that the examined Si-DLC coatings are not cytotoxic, regardless of the Si concentration. Only a slight decrease in the endothelial cells' proliferation was observed with the growing Si content. Hence, it was concluded that the Si-DLC layer with the Si concentration ~ 16 at.% would be the most bio- and haemocompatible.

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